Sewing mechanism



Feb. 11, 1941. 'T, H D P IN 2,231,566

SEWING MECHANISM Filed Dec. 11, 1939 5 Sheets-Sheet 1 m m 5 6 H Feb. 11, 1941. DE SP IN 1 2,231,566

SEWING MECHANISM Filed Dec. 11, 1939 5 Sheets-Sheet 2 Feb. 11,1941. U SP IN 2,231,566

SEWING MECHANISM Fi led Dec. 11, 1939 5 Sheets-Sheet 3 m I v R I 3mm E Thomas H DeSpapL,

fHLs awn/mags Feb. 11-, 1941. T. H. DE SPAIN SEWING MECHANISM Filed Dec. 11, 1939 5 Sheets-Sheet 4 Feb. 11, 1941. 1-. H. DE SPAIN SEWING MECHANISM Filed Dec. 11, 1939 5 Sheets-Sheet 5 Patented Feb. 11, 1941 UNITED STATES PATENT OFFICE SEWING 'MECHANISM Application December 11, 1939, Serial No. 308,711

8 Claims.

This invention relates to improvements in sewing mechanisms and, particularly to sewing mechanisms for that type of sewing machine known. as a dial .looper.

Sewing machines of this type, or the diallooper type, comprise a series of work-supporting elements, commonly called work points, on which the'loops of the work tobe sewed or united are impaled and advanced past the sewing mechanism which usually comprises a reciprocatory thread needle and a looper. The work-supporting points are in dial formation so that they constitute an endless series and, in use, separate pieces of work are successively placed on the work points slightly spaced apart. It is, therefore, desirable to provide means which will prevent fouling of the thread after one piece of work has passed the sewing mechanism and before the next piece of work has reached that mechanism. This'fouling of threads at these particular points in the rotation of the work dial is prevented by the provision of means on which the sewing mechanism can continue to form stitches. In other words, a chain of stitches is formed between each two successive pieces of work operated upon. It is this particular operation from which comes the term chaining-off.

The primary object of the present invention is to provide an improved, but simplified, chainingoff device or chain stitch mechanism in a dial looper having, a sewing mechanism which produces a two-thread seam.

Another. object is to provide a chain stitch mechanism. which will not only function to permit the formation of the chaining-off stitches, but will also actually function while the sewing mechanism is engaged with work on the dial points functioning, in this latter instance, for the purpose of producing a limited amount of slackin the stitches formed by one of the threads ofthe seam,

Still another object of the. invention is to form a two-thread seam wherein one threadis passed around the stitch finger at one side of the work and through the work to the opposite side where it is formed into successive loops, while the second thread of the seamis also formed into successive loops at the opposite side of the work with each loop of the second thread extending through one loop of the first thread and around 'a second loop of said first thread. In other words, the first thread is passed through work and. formed into loops, each of which is held against withdrawal from the work by a loop of the second thread and the loop of the second thread is held from withdrawal from the loop of the first thread by means of a second loop in the first thread.

More specifically, the invention contemplates a sewing mechanism preferably combined with the chaining-off attachment comprising a chain stitch finger so positioned with respect to the work-supporting points that it will lie close to the loops of work on said points at one side of the Work and the thread needle of the sewing mechanism, when advanced through the loops of the work, will pass, first, on one side of the finger and then on the other, so that the thread 1 spect to one another that successive loops will be H formedin the needle thread by the looper at the side of the work opposite the stitch finger and successive loops will be formed in the looper thread by the needle with each of the looperthread loops extending through one of the needle-thread loops and around a second needlethread loop. As the work progresses by the advancing movement of the work points, the loops of needle thread formed around the finger at the side of the seam slip off of the finger and, when thus freed, the additional thread required in passing it around the stitch finger results in a comparatively loose seam.

With these and other objects in view, the invention consists in certain details of construction and combinations and arrangements of parts, all as will hereinafter be more fully described, and the novel features thereof particularly pointedout in the appended claims.

In the accompanying drawings-- Figure 1 is a top plan view of a section of the dial of a dial looper, illustrating the present sewing mechanism and stitch finger, together with the operating connections for those elements;

Fig. 2 is avertical sectional view through the dial in substantially the plane of the thread needle;

Fig. 2 is a similar view showing the second position of the stitch finger;

Figs. 3 to 10, both inclusive, illustrate a cycle of the movements of the thread needle, looper and stitch finger;

Fig. 11 is a detail sectional view on the line H-ll of Fig.1;

to an eccentric 38 on shaft 2|.

Fig. 12 is a detail perspective view of the looper element; and

Fig. 13 is a more or less diagrammatic illustration of the stitches constituting the present twothread seam.

As indicated, a so-called dial-looper sewing machine has been adopted for purposes of illustrating the present invention. A machine of this type is more fully illustrated and described in applicants United States Letters Patent Nos. 2,050,563, August 11, 1936, and 2,167,104, July 25, 1939, and, as the present invention is not concerned with the specific construction of machines of this type, a detailed description of the same is deemed unnecessary here. For purposes of imparting a, full understanding of the present invention, the machine illustrated may be described as comprising a base 20 formed with suitable bearings for a main drive shaft 2| to which power is supplied from a suitable source by means of pulley 22 controlled by a clutch mechanism 23. The base has a rigid overhanging arm 24 and supported from said arm is a bed plate 25 having a peripheral guard in which there is rotatably supported a sectional ring member 26 formed on its under surface with a ring gear 21. Meshing with this ring gear is a gear (not shown) driven from a shaft 28 which, in turn, is driven by a shaft 29 through gears 30, 3|. Shaft 29 is driven from the main shaft 2| by gears 32, 33. Clamped in the ring 23 is the circular series of work-supporting pins or points 34 and, in the present type of machine, this series of points is continuously rotated so that the several points are successively advanced past the sewing mech anism which comprises the thread needle 35. As the loops of work on each point come into registry with the thread needle, the latter is projected through the work, as is well understood, said needle being reciprocated lengthwise of thework points by link 36 connected at one end to the needle arm 31 and at the opposite end Lateral or stepover movement of the needle which is necessary by reason of the continuous motion of the work points is effected by a lever 39 provided at one endwith a-cam roller running-in a-cam-way 40 on shaft 2|, and pivotally attached at itsv opposite end to an extension 4| of the needle arm, whereby the latter can be shifted back and forth on the shaft 42 on which said needle arm is pivoted.

Each time the needl 35 is advanced and projected through the work, the thread carried by the needle is engaged by a looper 43, whereby a loop of the needle thread is retained on theloopor during retraction of the needle and until, the next succeeding advance movement thereof. The needle, on the next succeeding stroke, engages a thread carried by the looper and forms a loop in the looper thread which looper thread extends through the previously formed needlethread loop to prevent withdrawal of that needlethread loop from the work. It should be stated at this point that, as the needle, during its advance movement, engages the looper thread to form a loop in the latter, this looper-thread loop Will be so formed as to not only extend through the previously formed needle-thread loop but will extend around the next succeeding needlethread loop so that the looper-thread loop cannot pull through the needle-thread loop through which it extends. This particular form of doublethread seam is clearly illustrated in Fig. 13, wherein the work loops are indicated at W, the

needle thread at N and the looper thread at L. In this figure, it will be seen that that portion of the looper thread constituting the loop L extends through the portion of the needle thread constituting loop N and. around that portion of the needle thread constituting loop N In other words, each looper-thread loop extends through one needle-thread loop and around a second needle-thread loop, so that the first-mentioned needle-thread loop cannot unravel or pull through the work and the looper-thread loop cannot be withdrawn from that needle-thread loop by reason of'the fact that it extends around a second needle-thread loop.

The movements of the needle 35 and the looper 43, in forming this two-thread stitch, are disclosed in the series of views, Figs. 3 to 10. Fig. 3 shows a loop of needle thread N around the looper 43 and the needle is about to penetrate the work on its next advanced movement, at which time the looper thread L is disposed through the loop of needle thread, the looper having been advanced to a point where the eye thereof for the looper thread is to one side of the path of movement of the needle, while the loop N of needle thread is at the opposite side of the advancing needle. Thus, as shown in Fig. 4, the needle passes between the upper surface of the looper and the looper thread so that, when the looper is retracted, as shown in Fig. 5, the previously formed loop of needle thread is dropped off but cannot pull through the work by reason ofthe looper thread extending therethrough and being retained in the form of a loop around the needle 35. As the needle is retracted from the position in which it is shown in Fig. 5, the looper is again advanced, as shown in Fig. 6, so that, when the needle has been fully retracted, preliminary to its next advance movement, another loop of needle thread will have been formed around the looper, as shown in'Fig. '7. It will be understood that, as the needle was retracted from the position shown inFig. 6 to the position shown in Fig. 7, leaving a loop of needle thread around the looper, the last-formed loop of looper thread will have been dropped from the needle, but this loop of looper thread cannot be withdrawn from the previously-formed loop of needle thread by reason of the fact that the last formed loop of needle thread (the one illustrated in Fig. '7) extends through the loop of looper thread. Fig. 7 clearly shows the form of the seam. as previously described. For instance, there is shown in this figure one loop of needle thread which has previously been dropped from the looper and a second loop of needle thread around the looper and the single loop of loo-per thread which has been formed at that time extends through the previously dropped loop of needle thread and thread around the needle, as shown in Fig. 9.

Fig. 9 also shows the looper again advancing to pick up the needle thread so that, as the needle is retracted to the position shown in Fig. 10,v

there is retained on the looper a loop of needle thread. It will again be understood that, as the needle is retracted, the loop of looper thread is dropped off. This completes the cycle of operations, as the loop of needle thread retained on the looper in Fig. 10 occupies in the cycle of operations the place of the loop of needle thread illustrated around the looper in Fig. 3.

This cycle of operations has been described in connection with loops of work on the work points, under which conditions there is no likelihood of the threads fouling but, as previously pointed out, when a portion of the circular series of needle points carrying no work passes this sewing mechanism, means must be provided for permitting the continued formation of stitches or in carrying out what has been termed the chainingoff operation. For this purpose, a stitch finger 44 is provided, said finger being disposed over the work points adjacent the path traversed by the work loops as the latter are advanced by the rotating dial. The stitch finger proper rests on the upper surface of the work points and is formed with an offset lateral extension which merges into a shank portion 45 adjustably secured by a screw 46 in a pivot pin 41 rotatable in an arm 48. In forming a loop of needle thread around the stitch finger 44, the needle is adapted to alternately pass at opposite sides of the finger during each two successive advance movements of the needle. In other words, when the needle is advanced toward the looper, it will pass under the stitch finger on one advance stroke and over the stitch finger on the next, succeeding advance stroke. For this purpose, the lateral extension of the stitch finger is offset from the horizontal plane of the finger (see Fig. 2) and is formed of revers'ely bent portions 49, Also, the arm 48 in which the pivot pin carrying the stitch finger is journaled is adapted to be actuated to raise pivoted on links 5| and provided with a cam roller journaled on a stud 52, said cam roller engaging in a cam 53 that will cause the arm 48 to be oscillated transversely of the stitch finger and to be depressed and lowered with respect to the needle. The stitch finger is illustrated in its lower position with the needle passing over it in Fig. 2 and, in Fig, 2 the stitch finger has been raised so that the needle will pass under it. Likewise, in Figs. 3 to 10, illustrating the formation of the stitches, it will be seen that the needle is passing over the offset portion 49 of the stitch finger in Figs. 3 to 6, and under said offset portion in Figs. 7, 8 and 9. Fig. 10, which shows the needle about ready to start the next, succeeding cycle of operations, illustrates the tip of the needle again passing over the offset portion 49. In this way, the needle thread N is looped around the stitch finger 44 upon each two successive advance movements of the needle. A detailed disclosure of the mounting and operation or manipulation of the stitch finger is given in applicants Patent No. 2,167,104, previously mentioned.

Referring to Fig. 10, for instance, several loop-s of needle thread are illustrated as extending around the stitch finger 44. Viewing this figure, it will be apparent that, as the sewing operation continues, the loops of thread around the finger will move toward the left along with the work, until they become disengaged from the finger. Likewise, in the absence of work, it will also be apparent from this figure that the needle, by passing first over and then under the stitch finger, will, in the same fashion, continue to form the loops around the stitch finger and, in conjunction with the looper and looper thread, a chain of interlocked stitches formed from two threads will continue to be produced, so as to absolutely preclude fouling of the threads, even under these conditions, i. e., in the absence of work.

Thus, the presence of the stitch finger permits the continued formation of a chain of interlocked stitches from the two threads, even though there is no work on the work points. Another advantage of having a stitch finger is that, when there is work present, the looping of the needle thread around the stitch finger will produce a comparatively loose seam because, after the loops of needle thread pass off of the stitch finger, there will be a certain amount of slack in the needle thread forming the loops or stitches. The principal feature of the present invention, therefore, might be said to reside in the provision of means for forming an interlocked two-thread seam in conjunction with the stitch finger whereby a comparatively loose seam can be produced.

Referring again to Figs. 3 to 10, it will be observed that the looper must not only move back and forth across the advanced needle, but must also pass over the needle to pick up the needle thread and under the needle to permit the needle to pick up the looper thread. Accordingly, the looper is carried on a looper arm 54, slidably supported in a guide 55 pivoted at 56 on a bracket 51. The end of the looper arm opposite the looper is disposed between cams 58 and 59. This end of the looper arm is of substantially arcuate formation and has cam rollers 60 and 5| on opposite sides thereof. Roller 60 engages cam-way 62 in cam 58 for reciprocating the looper back and forth across the path of the needle and roller 61 engages in cam-way 63 in cam 59 for rocking the cam arm and its pivoted guide on the pivotal center 56 of the guide to raise and lower the looper with respect to the path of the needle.

What I claim is:

1. In a sewing machine comprising a thread needle, means for advancing said needle through work to be stitched, a stitch finger disposed longitudinally of the seam formed in the work and means for causing the needle and its thread to pass alternately at opposite sides of said finger during successive advance movements thereof, a looper carrying a looper thread, and mechanism actuating said looper to engage and hold a loop of needle thread with the looper thread extending through said loop while said needle is retracted and advanced to form a loop in the looper thread and carry the needle thread through said looper-thread loop said looperactuating mechanism comprising means for reciprocating the looper transversely of the needle and for oscillating said looper relatively to the needle.

2. In a sewing machine comprising a series of work-supporting points, a thread needle, means for advancing the points past the needle, a stitch finger disposed substantially parallel to the line of movement of said points, means for advancing said needle past said finger alternately at opposite sides of the finger and a looper having a looper thread and means for reciprocating and oscillating, said looper to engage the needle thread and form a loop therein each time the needle is advanced and to position the looper thread through the needle-thread loop in the path of the needle for the latter to form a loop in the looper thread with the needle thread extending through the looper-thread loop.

3. In a sewing machine comprising a series of work supporting points, a thread-carrying needle, means for advancing said points past the needle, a stitch finger disposed substantially parallel to the line of movement of said points, a thread-carrying looper, means for oscillating said looper relatively to the needle, means for advancing said needle past said finger alternately at opposite sides of the latter and through work on said points to carry the needle thread past said looper, said needle being movable between the looper and looper thread to form successive loops in said looper thread, and means for advancing and retracting the looper transversely of the advanced needle to form successive loops in the needle thread, each looper thread loop extending through a needle thread loop and around the next successive needle thread loop.

4. In a sewing machine comprising a threadcarrying needle, a thread-carrying looper, means for feeding work between the needle and looper,

means for advancing and retracting the needle and its thread through the work, means for oscillating said looper relatively to the needle, said needle being movable between the looper and looper thread, means for advancing said looper past the advanced needle to form a loop in the needle thread, and a stitch finger extending lengthwise of the seam formed in the work, said needle thread being carried past the finger alternately at opposite sides of said finger during successive advance movements of the needle.

5. In a sewing machine comprising a thread needle, means for advancing and retracting the needle and thread carried thereby through work to be sewed, a stitch finger extending along one side of the work, means for directing successive advance movements of the needle past said finger at opposite sides of the latter, a second thread carrier at the opposite side of the work, means for reciprocating and oscillating the second thread carrier relatively to the needle, said second thread carrier being engageable with the needle thread to form successive loops therein at said opposite side of the work, said needle being engageable with the second thread to form successive loops therein with each loop of said second thread extending through a needle-thread loop and around a subsequently formed needlethread loop.

6. In a sewing machine, work-supporting,

means, a thread needle and a stitch finger disposed at one side of work on said support, a thread-carrying looper at the opposite side of the work, means for advancing the needle past the finger alternately at opposite sides of the latter and through the work to form loops in the needle thread around the finger, means for advancing the looper transversely past the advanced needle at the looper side of the work, and means for oscillating said looper relatively to the needle, said looper engaging the needle thread on its alternate advance movements to form loops therein and said needle engaging the looper thread on 1 the other alternate advances of the looper to form loops in said looper thread with each looperthread loop extending around a needle-thread loop and through a second but previously formed needle-thread loop.

'7. In a sewing machine, a thread needle, a thread-carrying looper, means for moving work between the needle and looper, means for advancing the needle through the work and past the looper, and means for moving the looper past the advanced needle and for oscillating said looper with respect to the needle, said looper engaging the needle thread on its alternate advance movements to form successive loops therein and said needle engaging the looper thread on the other alternate advance movements of the looper to form successive loops in the looper thread, each looper-thread loop extending through one needle-thread loop and around a second needle-thread loop whereby the first needlethread loop is locked in the work by the looperthread loop and said looper-thread loop is locked in the first needle-thread loo-p by said second needle-thread loop.

8. In a sewing machine, a thread needle, a thread-carrying looper, means for moving work between said needle and looper, means for advancing the needle through the work past the looper, actuating means for advancing the looper with its thread between the advanced needle and needle thread to hold a loop of needle thread while the needle is retracted, said actuating means being operable to oscillate said looper and position it with respect to the needle during the next succeeding advance of the latter to permit said needle to pass between the looper and looper thread at a point between the looper eye and the needle-thread loop held by the looper.

THOMAS H. DE SPAIN. 

